EEVBlog #862 - BK Precision 8601 DC Electronic Load

[EEVblog]

Dave takes a look at the BK Precision 8601 DC Electronic Load and compares with his older 8500 model.
A teardown and some playing around with the software

[Stonent]

I was up in the electronics lab at work and they had a BK Precision 2500W programmable load on their bench.
Probably was a full 4U rack mountable device, but it was just sitting on their bench.

[EEVblog]

I was up in the electronics lab at work and they had a BK Precision 2500W programmable load on their bench.
Probably was a full 4U rack mountable device, but it was just sitting on their bench.

Not uncommon to find rack mount gear on the bench.
Racks are great for production test systems etc, but a PITA for general use. So yeah, just whack'em on the bench.

[n3vti]

Aww, this looks awesome! I can't afford the $1100 so I have to put this on my Wish List. It does make for some good drooling, though.

[Gareth Lock]

I couldn't help but notice that you weren't actually using MS Excel at all, but LibreOffice. If the software is expecting to drop the data straight into Excel, then, could it be that the option is disabled as it has detected that Excel isn't actually installed on the computer.

[Bud]

The company is Maynuo. They have an interesting history and I am privy to it. Not what you might think if you listen to BK Precision.

http://dc-electronic-load.com/
The sales contact is Kate Zhou

I visited the link and was immediately chased by two annoying nag screens in a typical Chinee-ish look and feel. Was enough for me to close the browser and never go back. Thank you very much Kate you just lost a customer because of agressive manner the web site is built in.

[EEVblog]

 

[n3vti]

FAIL lol   

[jancumps]

The company is Maynuo. They have an interesting history and I am privy to it. Not what you might think if you listen to BK Precision.

http://dc-electronic-load.com/
The sales contact is Kate Zhou

I visited the link and was immediately chased by two annoying nag screens in a typical Chinee-ish look and feel. Was enough for me to close the browser and never go back. Thank you very much Kate you just lost a customer because of agressive manner the web site is built in.

Very surpised to hear that. Last time I dealt with Maynuo, the website was different. i sent an email to kate with a few questions and got a pleasant, fast response. They offered to ship to me direct and that was it....quick and simple. I then did again for one of their supplies. The transactions were smooth. Apparently, they are not doing their business any good by chasing away customers like you with annoying tactics.

It's not that bad. Just visited the website and those widgets aren't aggressive at all.

[EEVblog]

Sorry Dave, Maynuo is NOT fake.

Well the story as I hear it (and it may be one side of the story), is that the Maynuo founder worked at Itech who did these designs (BK Precision take the Itech designs and tweak them) and then illegally ran off with all the IP.
If that is incorrect then he's welcome to come here and tell his side of the story.

[RobertoLG]

The company is Maynuo. They have an interesting history and I am privy to it. Not what you might think if you listen to BK Precision.

http://dc-electronic-load.com/
The sales contact is Kate Zhou

I visited the link and was immediately chased by two annoying nag screens in a typical Chinee-ish look and feel. Was enough for me to close the browser and never go back. Thank you very much Kate you just lost a customer because of agressive manner the web site is built in.

maybe you should "improve" your browser, or use another one, like firefox

[Brumby]

Basic Output/Input System

Still means the same thing.   


(but I did LOL)

[EEVblog]

Sorry Dave, Maynuo is NOT fake.

Well the story as I hear it (and it may be one side of the story), is that the Maynuo founder worked at Itech who did these designs (BK Precision take the Itech designs and tweak them) and then illegally ran off with all the IP.
If that is incorrect then he's welcome to come here and tell his side of the story.

I heard that as well, from the principal dude at Manyou.

So he readily admitted to stealing the designs from Itech?

[Stonent]

I was up in the electronics lab at work and they had a BK Precision 2500W programmable load on their bench.
Probably was a full 4U rack mountable device, but it was just sitting on their bench.

Not uncommon to find rack mount gear on the bench.
Racks are great for production test systems etc, but a PITA for general use. So yeah, just whack'em on the bench.

Yeah, all their stuff is on their benches. I've lost count how many 3GHz Spectrum Analyzers they have.  We don't even do any RF stuff that I know of but I'm sure the range is handy for other reasons.

Here it is:



The interface is the same as the 300W version. Makes sense to me.

[Barny]

Dave, did you use a Zero-Modem RS232 cable?
Perhaps that was the reason, no data got through.

[motocoder]

Looks like they have a 120V 30A model (8600) that is a few hundred dollars (USD) less. Half the power, but otherwise same features.

May be time to unload that Array Solutions model that I am unable to update the firmware on.

[nowlan]

Im sure Maynuo is good value, but weren't they playing games with domestic vs export quality and prices?
Not sure who designed the BK listed above. Planning to watch later.

[EEVblog]

Dave, did you use a Zero-Modem RS232 cable?
Perhaps that was the reason, no data got through.

I used the specific isolated one that came with my 8500.

[EEVblog]

Not sure who designed the BK listed above. Planning to watch later.

The BK ones are essentially designed by Itech. But BK does make their own mods to the designs I'm lead to believe.

[mcinque]

Despite the true details of the Maynuo/BK precision engineering will be never revealed (every company says what they want), AFAIK Maynuo DC loads had that kind of specs (quad display, resolution etc.) much before than BK Precision came on market with the new model.

So, since this and considering the influence of your videos, I would reconsider that "Maynuo are rip-off" on the video. Just my thought.

EDIT: I heard from Maynuo that the engineer took the designs BECAUSE he wasn't paid by BK for the original project. BK say the he took the design after being paid.

[Zbig]

Despite the true details of the Maynuo/BK precision engineering will be never revealed (every company says what they want), AFAIK Maynuo DC loads had that kind of specs (quad display, resolution etc.) much before than BK Precision came on market with the new model.

So, since this and considering the influence of your videos, I would reconsider that "Maynuo are rip-off" on the video. Just my thought.

EDIT: I heard from Maynuo that the engineer took the designs BECAUSE he wasn't paid by BK for the original project. BK say the he took the design after being paid.

Exactly, two-line VFD Maynuo series 98xx is available since ages now.

[Switching Power]

I used the specific isolated one that came with my 8500.

The 8601 has the IO isolated internally so it uses a normal 1:1 serial cable (it even says so in the manual)

[nctnico]

Sorry Dave, Maynuo is NOT fake.

Well the story as I hear it (and it may be one side of the story), is that the Maynuo founder worked at Itech who did these designs (BK Precision take the Itech designs and tweak them) and then illegally ran off with all the IP.
If that is incorrect then he's welcome to come here and tell his side of the story.

I heard that as well, from the principal dude at Manyou.

So he readily admitted to stealing the designs from Itech?

Unless the PCB's and firmware are 100% the same the design isn't stolen. If you have created designs based on a certain microcontroller and switch employers (or start your own busines) it isn't stealing to use the knowledge you have gained for new designs.

[rizzy]

There had been a discussion on this forum about the BK Precision vs. Maynuo thing before:
https://www.eevblog.com/forum/testgear/why-is-bk-precision-still-in-business-bk8500-programmable-load-oem-found/

If it is true that the lead engineer of the 8500 founded Maynuo then I would not call that "stealing the designs" because it were somewhat his designs, although I agree that the Maynuos are blatant copies. I'm tending to believe that the post from kmel (from the above mentioned thread) is substantially right because all the listed test gear definitely has a very similar design. We will probably never find out the truth because either side will tell something different.

Anyway, I'm not a lawyer and also don't want to become one and as such I will leave all the stuff about "stealing IP" up to those who (or at least want to) earn their living with it. I'm really more interested about the the technical aspects of the electronic load, especially the specs and the precision.

At about 33:20 in the video, the software reads 1.4 mA before Dave turns on the load and it reads 9.1mA afterwards. At first I thought that's not within spec but after doing the math I realized that it was. In the "low" current settings of 0-3A you have an error in the accuracy of at least 3A*0.025% = 0.75mA but then for the readback of the current you have an additional 3A*0.05% = 1.5mA. So after all you get a spec of 22.5% of error if you want to draw 10mA. That does not sound like a suited device for measuring battery current in the low mA range.

[EEVblog]

If it is true that the lead engineer of the 8500 founded Maynuo then I would not call that "stealing the designs" because it were somewhat his designs

If you are employed as a designer for a company, then (unless you have special prior agreements) the designs and IP you come up with belong to the company.
Taking any technical information and design files etc.al with you when you leave is theft. And that's what happened according to BK Precision.
Of course you are free use whatever information is in your head and rebuild the product from scratch (subject to the usual copyright  and trademark and patent laws), but in this case, actual design files were supposedly taken.